2,428 research outputs found

    Consistent Construction of Perturbation Theory on Noncommutative Spaces

    Full text link
    We examine the effect of non-local deformations on the applicability of interaction point time ordered perturbation theory (IPTOPT) based on the free Hamiltonian of local theories. The usual argument for the case of quantum field theory (QFT) on a noncommutative (NC) space (based on the fact that the introduction of star products in bilinear terms does not alter the action) is not applicable to IPTOPT due to several discrepancies compared to the naive path integral approach when noncommutativity involves time. These discrepancies are explained in detail. Besides scalar models, gauge fields are also studied. For both cases, we discuss the free Hamiltonian with respect to non-local deformations.Comment: 22 pages; major changes in Section 3; minor changes in the Introduction and Conclusio

    Jurisprudence That Necessarily Embodies Moral Judgment: The Eighth Amendment, Catholic Teaching, and Death Penalty Discourse

    Get PDF
    The article compares the U.S. Jurisprudence with the death penalty teaching of the Catholic Church through a court case of Patrick Kennedy v. Louisiana Supreme Court. It focuses on the Eighth Amendment Jurisprudence and argues on the translated approach of Catholic Church to advance the death penalty discourse. The article also discusses moral judgment embodied by the Eighth Amendment Jurisprudence

    Coherent motion of stereocilia assures the concerted gating of hair-cell transduction channels

    Full text link
    The hair cell's mechanoreceptive organelle, the hair bundle, is highly sensitive because its transduction channels open over a very narrow range of displacements. The synchronous gating of transduction channels also underlies the active hair-bundle motility that amplifies and tunes responsiveness. The extent to which the gating of independent transduction channels is coordinated depends on how tightly individual stereocilia are constrained to move as a unit. Using dual-beam interferometry in the bullfrog's sacculus, we found that thermal movements of stereocilia located as far apart as a bundle's opposite edges display high coherence and negligible phase lag. Because the mechanical degrees of freedom of stereocilia are strongly constrained, a force applied anywhere in the hair bundle deflects the structure as a unit. This feature assures the concerted gating of transduction channels that maximizes the sensitivity of mechanoelectrical transduction and enhances the hair bundle's capacity to amplify its inputs.Comment: 24 pages, including 6 figures, published in 200

    Truss Parametrization of Topology Optimization Results with Curve Skeletons and Meta Balls

    Get PDF
    Truss-like shapes can occur in topology optimization described by an assembly of finite elements or its boundary represented as a polygon mesh. Such shape description does not cover a common engineering parametrization like the lines of a frame structure and its corresponding cross-section. This article addresses the truss-parametrization of such optimization using curve skeletons and Meta Balls. While the curve skeleton is common in the truss-parametrization, including Meta Balls can lead to an overall implicit and smooth shape description

    Control of Silica Dust in Slate Milling Operations

    Get PDF
    The Mine Safety and Health Administration (MSHA) conducted a study to assess the present state of technology used for controlling employees\u27 respirable silica-bearing dust exposures during dimension slate milling operations. For this study, twelve slate milling operations were visited and various measurements were taken and observations made. These measurements and observations included exhaust and room airflow, types of enclosures, water usage, and building volumes for each of the milling processes. These mills usually employed between five and twenty people. From the study, general guidelines were developed from the best practices observed and can be used at the various sawing, splitting, trimming, and drilling operations throughout the industry

    Effects of topology optimization in multimaterial 3D bioprinting of soft actuators

    Get PDF
    Recently, there has been a proliferation of soft robots and actuators that exhibit improved capabilities and adaptability through three-dimensional (3D) bioprinting. Flexibility and shape recovery attributes of stimuli-responsive polymers as the main components in the production of these dynamic structures enable soft manipulations in fragile environments, with potential applications in biomedical and food sectors. Topology optimization (TO), when used in conjunction with 3D bioprinting with optimal design features, offers new capabilities for efficient performance in compliant mechanisms. In this paper, multimaterial TO analysis is used to improve and control the bending performance of a bioprinted soft actuator with electrolytic stimulation. The multimaterial actuator performance is evaluated by the amplitude and rate of bending motion and compared with the single material printed actuator. The results demonstrated the efficacy of multimaterial 3D bioprinting optimization for the rate of actuation and bending

    Identifikasi Pengaruh Penggunaan Heatsink Terhadap Keluaran Modul Surya

    Get PDF
    Panas matahari yang diserap oleh modul surya dapat menaikkan suhu dan menurunkan tegangan keluarannya. Upaya penurunan suhu modul surya agar dalam kondisi standar diperlukan untuk menjaga agar kinerjanya tetap optimal. Pemasangan bahan penyerap panas seperti heatsink merupakan salah satu metode yang dapat digunakan sebagai upaya mendinginkan modul surya. Heatsink mampu mengurangi suhu rata-rata modul surya hingga 2,43°C dan meningkatkan tegangan keluaran rata-rata modul surya hingga 2,23 Volt. Kondisi ini dapat dilihat dari rata-rata tegangan output Voc modul surya yang ditambahkan heatsink dapat mencapai tegangan rata- rata 20,76 Volt dibandingkan dengan modul tanpa penambahan heatsink 18,52 Volt. Disimpulkan bahwa penambahan bahan penyerap panas berupa heatsink lebih efektif menurunkan suhu modul surya dari pada tanpa menggunakan heatsink

    Full oxide heterostructure combining a high-Tc diluted ferromagnet with a high-mobility conductor

    Full text link
    We report on the growth of heterostructures composed of layers of the high-Curie temperature ferromagnet Co-doped (La,Sr)TiO3 (Co-LSTO) with high-mobility SrTiO3 (STO) substrates processed at low oxygen pressure. While perpendicular spin-dependent transport measurements in STO//Co-LSTO/LAO/Co tunnel junctions demonstrate the existence of a large spin polarization in Co-LSTO, planar magnetotransport experiments on STO//Co-LSTO samples evidence electronic mobilities as high as 10000 cm2/Vs at T = 10 K. At high enough applied fields and low enough temperatures (H < 60 kOe, T < 4 K) Shubnikov-de Haas oscillations are also observed. We present an extensive analysis of these quantum oscillations and relate them with the electronic properties of STO, for which we find large scattering rates up to ~ 10 ps. Thus, this work opens up the possibility to inject a spin-polarized current from a high-Curie temperature diluted oxide into an isostructural system with high-mobility and a large spin diffusion length.Comment: to appear in Phys. Rev.

    Control of a SiC 2.5 MHz resonant full-bridge inverter for inductively driven plasma

    Get PDF
    The electronic ballast of an inductively driven plasma faces a mostly inductive, variable load impedance. The SiC full-bridge inverter uses the inductive behavior to achieve zero-voltage-switching and a switching frequency of 2.5 MHz, at 3.9 kVA and 764W in the plasma. The control is realized on a modern, small TI Piccolo microcontroller with a high-resolution PWM module and compensates for the variable load impedance. We present design and experimental results of a 2.5 MHz inverter for inductively driven plasma without the need for a large FPGA controller
    • …
    corecore